 Fuel Pressure Revisited |
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| jdogg |
 Feb 23 2003, 07:57 PM
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#1
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Member  Group: Members Posts: 431 Joined: 28-January 03 From: Youngsville, NC Member No.: 204  |
Thanks to all the posts and the fine pics from DD and Brad, I got my fuel pressure guage installed and running in no time flat today. My question is now this....it's reading 35 psi - too much pressure - is this something that is adjustable at the regulator, or does it indicate another problem, possibly a clogged return line?
What symptoms would an over-pressurized fuel system exhibit? |
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Replies(1 - 5)
| 2teeners |
Feb 23 2003, 08:47 PM
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#2
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Member Group: Members Posts: 79 Joined: 2-January 03 From: Arlington DFW, TX Member No.: 78 |
Some people recommend a raised fuel pressure to combat vapor locking, and a richer fuel mixture. 35 is probably tops though. You can adust it down by backing off the adjusting screw on the regulator, left rear of the engine compartment with the fuel lines connected to it.
What sort of fuel pressure should be run to carbs in a 6 cylinder setup? Does anybody in a conversion ever use a standard FI pump and stop it down to the lowered number? |
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| Gint |
Feb 23 2003, 09:15 PM
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#3
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Mike Ginter Group: Admin Posts: 16,075 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains  |
I wouldn't run it at 35. Spec is what, 29? 32 or 33 max IMHO.
QUOTE What sort of fuel pressure should be run to carbs in a 6 cylinder setup? Does anybody in a conversion ever use a standard FI pump and stop it down to the lowered number? NO. Sixes need 3.5 psi (carbs). The factory /6 pump *looks* like a factory /4 FI pump, but it's not. It doesn't put out nearly as much pressure as the FI pump. If I were to replace mine, I would use a standard generic electric fuel pump. |
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| Brad Roberts |
Feb 23 2003, 09:21 PM
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#4
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914 Freak! Group: Members Posts: 19,148 Joined: 23-December 02 Member No.: 8 Region Association: None |
One of my Bosch manuels buried someplace says for fuel pressure: 28. 30 in hot weather area's.
DO NOT try to regulate down the factory pump. I know of more than one car that burned to the gorund this way when they went to carbs. One of them is a "ASE" certified mechanic that frequents Rennlist. His wifes 1.8 injection was giving him fits... so he temporarly converted the car to carbs. It burnt less than 15 minutes from his house. 3.5 for the sixes... B |
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| 2teeners |
Feb 24 2003, 06:40 AM
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#5
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Member Group: Members Posts: 79 Joined: 2-January 03 From: Arlington DFW, TX Member No.: 78 |
i saw a diagram that showed a 6 setup which appeared to use the return fuel line, which is what prompted the question. I'll use the generic pump and regulator.
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| Bleyseng |
Feb 24 2003, 12:26 PM
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#6
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Aircooled Baby! Group: Members Posts: 13,034 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
35 lbs is tops for setting the fuel pressure. The injectors start spraying a stream instead of a mist after that. Problems or symtoms of higher pressure, rich mixture. This was often the solution to a car having lean running problems, just crank it up. Saw it recently at a PCA Club dyno event where the "Tuner" tuned a 2.0L that was running lean that way. Course the car was running 1.7 djet but that couldn't have been why! Sometimes no one listens.....
Geoff :finger2: |
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